1. Field of the Invention
The present invention relates to the technological field of liquid crystal production, and more particularly, to a low temperature poly-silicon thin-film transistor (LTPS TFT) having a dual-gate structure and a method for forming the LTPS TFT.
2. Description of the Prior Art
Technology on LTPS TFTs has developed and advanced to a certain extent. Compared with amorphous silicon (often abbreviated a-si) and oxidation, LTPS TFTs have higher carrier mobility, which means that LTPS TFTs are good for enhancing the driving ability of devices and reducing power consumption of devices. Moreover, an LTPS TFT can be a part of a complementary metal oxide semiconductor (CMOS) circuit. The circuit reliability of a gate driver on array (GOA) which uses the CMOS circuit increases. In the manufacturing process of CMOSs, the doping of a lightly doped drain (LDD) of an N-type metal-oxide-semiconductor (NMOS) can be conducted through a single mask. Or, a lightly doped drain (LDD) of an N-type metal-oxide-semiconductor (NMOS) can be doped through the gate over wet etching. It is not necessary to use a mask in the latter manufacturing process of CMOSs, but the latter manufacturing process of CMOSs may have a poor yield rate.
A mainstream structure of the conventional LTPS TFT is famous for a top gate structure. Photo leakage current easily occurs on channels when a conventional LCD shows images without any shielding layers.